Soldering skillz

My finished Adafruit breadboard power supply, delivering a stable 5.04V. Read on to see how much practice it took me to get to this point.

I’ve posted quite a few breadboard circuits over the last few months. They’re quick, easy, and temporary. They’re also easy to modify and debug, which has been very important for me. Still, if I want to do something more complex, or something that’s going to be permanent, I need to be able to solder components together.

Easier said than done.

If you set out to try new things from time to time, you’re guaranteed to eventually hit something you have absolutely no knack for. That’s been my experience with soldering irons. Not that I haven’t had some good results – it’s just that I’ve also had a few bad results, and a heck of a lot of ugly results. I’ve been working at it on and off for months, and I’m just getting to the point where I have a kind of basic competence.

If you look carefully at the right edge, you can see where this project went badly awry. At least it gave me a board I could use to practice desoldering.

You wouldn’t figure it’d be that hard. A soldering iron is not a complicated tool – it’s about one step removed from sticking a fork in an electric socket, after all. You just use it to apply heat where the component meets the pad on the circuit board, and then stick some solder in so it melts and bonds the pieces together. The concept is entirely straightforward. It’s the execution that’s tricky.

I’m usually pretty good at tasks that require fine detail, but I only have two hands. Four would be ideal – one to hold the solder, another for the iron, one for the circuit board, and one more to keep the component I’m soldering from wiggling around. Five hands, if I wanted to take pictures. A pair of helping hands will only help so much, you know?

Still, I think timing is my biggest challenge. You’ve got to time it to provide the right mount of heat. The cold solder joints and burnt pads I’ve left in my wake are a grim testimonial to the challenges I face in this arena.

The good news is that there are a lot of cheap little kits for me to practice on. Some of them have been easier on me than others. Most of the ones I’ve tried have worked – just not on the first try. My goal for developing these skills is to be able to put together something like the Briel Computers Micro-KIM – a single board replica of Commodore’s first computer board. At $109, though, I want to make sure I know what I’m doing before I try to build one.

I’ve been practicing on some smaller kits while watching the recent Presidential and Vice-Presidential debates. I think I would have found the debates a lot more frustrating without something to keep my hands busy, though I’m not sure if that’s a good thing or a bad thing. On the other hand, if I can stay calm enough to get good results while watching [CANDIDATE I’M NOT VOTING FOR] badmouth [CANDIDATE I AM VOTING FOR], that’s probably a sign of a real improvement in my skills.

After two attempts, a working version of the sound-to-light kit!

The first project I did was a sound-to-light kit from Velleman. It’s actually a tricky kit to work on, because the components are all jammed onto the smallest possible circuit board. This was my second attempt at this particular kit – the first try ended in disaster while I was trying to solder the four LEDs into place. After creating what looked like a good join, I touched one of the LEDs with my finger and the entire pad just separated from the circuit board. While futilely trying to fix that problem, I got too much heat too close to the LEDs, and they started to fail. Ultimately, I used the wrecked board to practice using desoldering braid to remove extra cruddy solder – which I’d left so much of behind.

My second try, despite anticipating the problem and being extra careful, the exact same thing happened, in the exact same place. Given that, I’m starting to wonder if there wasn’t something weird about the boards themselves. On the other hand, this time around I was able to kluge together a fix to restore some of the connections I’d screwed up with a bit of scrap wire. The result may be another entry for the “Ugly” column, but it did in fact work.

One way to build confidence is to try something simple, like this Pi Cobbler breakout board for the Raspberry Pi’s IO pins.

My second practice project was something nice and straightforward – the Pi Cobbler breakout board from Adafruit. It’s basically just a little adapter that you use to connect a Raspberry Pi across a piece of ribbon cable to a breadboard. The part that requires soldering is only four pieces – a small circuit board, the connector for the cable, and a couple rows of header pins. Each of these parts had a bunch of connections that required soldering, but it was really easy to just go down each line and make each connection. The project worked the first time, which is kind of unusual for me.

After the success of the Pi Cobbler, and with a long discussion on foreign policy to sit through, I decided to try another Adafruit kit that had been in my build queue for a while – a breadboard power supply kit. I’ve been running most of my breadboard projects off of batteries, but that means the voltage can vary as the batteries start to lose power, and for some of the things I want to do next I need something more certain. This power supply kit is adjustable to provide 3.3v, 5v, or a variable voltage source.

By the way, I know this post is starting to sound like an ad for Adafruit, but I want to assure you that I’m not getting any kickbacks from them. Unfortunately.

The unassembled power supply kit. Boy, that’s a lot of different pieces to work with…

The power supply kit was really good practice for me. It had a combination of parts with large posts that form mechanical connections (the power input jack itself) and smaller ones that required precise work (the 3-position voltage selector switch). Plus the kit instructions were really well thought out, and the build order allowed for incremental testing. For once, I was able to complete a moderately complicated kit without any big missteps, and I’m feeling pretty good about that.

Maybe not good enough to jump straight to the Micro-KIM, but maybe good enough for this RS-232 Terminal kit. I just need to come up with something to use it for!